Articulated shaft

ABSTRACT

In an articulated shaft for the transfer of torque from a transmission to a differential drive, including a connecting flange having a tube section, a shaft plate disposed between the connecting flange and a transmission output flange and forming a torsion element for accommodating some articulation of the connecting flange relative to the output flange, and a centering part extending from the connecting flange for aligning the articulated shaft relative to a transmission shaft, the connecting flange is formed integrally with the tube section by deep drawing and punching, the centering part being pressed into the tube section.

BACKGROUND OF THE INVENTION

The invention relates to an articulated shaft for the transmission of a torque form a transmission to a differential drive of a motor vehicle, including a connecting flange with a tube section for coupling the articulated shaft with a transmission output flange, an articulation disc which forms a torsion element and accommodates also some misalignment and a centering part for aligning the articulated shaft with respect to a transmission pivot, which is pressed into the connecting flange.

An articulated shaft with these features is known from DE 199 54 475 C1. The connecting flange of the articulated shaft described therein is a forged component which is manufactured in three steps. In the first manufacturing step, the connecting flange is forged to an unfinished product. In the second manufacturing step, a tube section for the connection to a hollow shaft is machined. In the third manufacturing step, the openings for the connecting bolts and a center opening for receiving the centering components are drilled. The articulated shaft is assembled by welding the tube section to the hollow shaft, pressing the centering component into the center opening, filling the centering component with grease and closing it with a cover. Because of the different types of manufacturing processes, the manufacture of the connecting flange including the tube section is very costly.

It is the object of the present invention to provide an articulated shaft which is easier and less expensive to manufacture.

SUMMARY OF THE INVENTION

In an articulated shaft for the transfer of torque from a transmission to a differential drive, including a connecting flange having a tube section, a shaft plate disposed between the connecting flange and a transmission output flange and forming a torsion element for accommodating some articulation of the connecting flange relative to the output flange, and a centering part extending from the connecting flange for aligning the articulated shaft relative to a transmission shaft, the connecting flange is formed integrally with the tube section by deep drawing and punching, the centering part being pressed into the tube section.

In accordance with the present invention, the connecting flange and the tube section which are formed by deep drawing, are manufactured within a follow-on tool in a single manufacturing step in which, furthermore, also the flange openings are punched out. Since, in comparison with the state of the art, two manufacturing steps are eliminated the costs of manufacturing the articulated shaft are reduced.

In a particular embodiment of the invention, a support element for centering the shaft plate with respect to the connecting flange is supported by the centering part. To this end, the support element is disc-shaped in a radial direction and pot-like in axial direction. The pot-like section again is centered at an annular collar of the centering part.

Preferred embodiments of the invention will be described below on the basis of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of an articulated shaft,

FIG. 2 shows a second embodiment of an articulated shaft, and

FIG. 3 shows an articulated shaft with a support element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows an articulated shaft 1 in accordance with a first embodiment. The articulated shaft comprises a centering part 6, a connecting flange 2 and a tube section 3. The connecting flange 2 and the tube section 3 are joined so as to be a single piece. A hollow shaft which is not shown is welded to the tube section 3 and extends to the differential gear. The centering part 6 is pressed into the connecting flange 2 and the tube section 3 over a length L. The resulting support area of the centering part 6 is larger than that of articulated shafts known in the art. As a result, an improved centering accuracy is achieved without increased expenses. By means of the centering part 6, the articulated shaft 1 is aligned with the transmission pivot 7 as the transmission pivot extends into the centering part 6. At the inner circumference of the centering part 6, an annular elastomer member 11 as well as a membrane with a venting opening 12 may be arranged which may be directly vulcanized onto the annular elastomer member or may be formed integrally therewith: In contrast to the centering part of the state of the art no cover is provided.

The torque is transferred from a transmission via the articulated shaft 1 to the differential gear and vice versa via a shaft plate 5 to the connecting flange 2 and then to the tube section 3. To this end, the transmission output shaft flange 4 and the shaft plate 5 are bolted together. By the shaft plate 5, the torsion vibrations in the drive line are attenuated. In addition, any slight kink in the drive line or off-center position of the differential gear can be accommodated by the shaft plate 5 and the elastomer 11.

In practice, the articulated shaft is manufactured as follows:

In a first manufacturing step, the connecting flange 2 and the tube section 3 are deep-drawn in a follow-up tool and bores 13 are punched into the flange 2. Then, in a second manufacturing step, the centering part 6 is deep drawn and the elastomer is vulcanized into it. Finally, in a third manufacturing step, the centering part 6 is pressed into the connecting flange 2 and into the tube section 3 over the length L.

In FIG. 2 another embodiment of the articulated shaft is shown. In this embodiment, a centering part 6A has an end section 14 which is folded inwardly. In this way, the spring stiffness of the centering part 6A is increased since its radial rigidity is increased in the core of the fold. Otherwise, the arrangement is the same as that of FIG. 1 so that the description of FIG. 1 applies also to FIG. 2.

FIG. 3 shows an articulated shaft 1 with a support element 8. The articulated shaft 1 comprises the centering part 6B, the connecting flange 2 and the tube section 3, which is formed integrally with the flange 2 or connected thereto so as to form a single piece. As centering part of course also the centering part 6 of FIG. 1 or the centering part 6A of FIG. 2 may be installed: Between the transmission output flange 4 and the connecting flange 2, the support element 8 and the shaft plate 5 are arranged. The support element 8 forms at its radially inner end a centering structure for centering the shaft plate 5 with respect to the connecting flange 2 during assembly. The support element 8 is disc-like in the radial direction and in the form of a sleeve 9 in axial direction. The sleeve 9 is supported on the annular neck 10 of the centering part 6B whereby the support element 8 and, as a result, the articulated disc 5 are centered radially with respect to the connecting flange 2. The three components are axially fixed relative to one another by way of screws.

The articulated shaft has the following advantages over conventional designs:

the manufacture of the connecting flange with the tube section is more cost-effective since two manufacturing steps are eliminated;

the support surface of the pressed-in centering part is larger whereby the centering accuracy is improved;

the support element facilitates the assembly, and

no cover is needed for the centering part. 

1. An articulated shaft (1) for the transfer of torque from a transmission to a differential drive, comprising a connecting flange (2) including a tube section (3) for coupling the articulated shaft (1) to a transmission output flange (4), a shaft plate (5) disposed between the connecting flange (2) and the transmission output flange (4) and forming a torsion element accommodating also some articulation of the connecting flange (2) relative to the output flange (4) and a centering part (6) pressed into the connecting flange (2) for aligning the articulated shaft (1) relative to a transmission shaft (7) said connecting flange (2) being formed integrally with the tube section (3) by deep-drawing and punching.
 2. An articulated shaft according to claim 1, wherein a support element (8) connected to the shaft plate (5) engages the centering part (6B) for centering the shaft plate (5) relative to the connecting flange (2).
 3. An articulated shaft according to claim 2, wherein the support element (8) comprises a disc section disposed adjacent the shaft plate (5) and a central sleeve section (9) engaging the centering part (6B).
 4. An articulated shaft according to claim 2, wherein the centering part (6B) includes a collar (10) projecting axially toward the output flange (4) and the support element (8) engages the collar (10) at its outer circumference for centering.
 5. A method for the manufacture of an articulated shaft (1) for the transfer of torque from a transmission to a differential drive, comprising a connecting flange (2) including a tube section (3) for coupling the articulated shaft (1) to a transmission output flange (4), a shaft plate (5) disposed between the connecting flange (2) and the transmission output flange (4) and forming a torsion element accommodating also some articulation of the connecting flange (2) relative to the output flange (4) and a centering part (6) pressed into the connecting flange (2) formed integrally with the tube section (3) for aligning the articulated shaft (1) relative to a transmission shaft (7), said method comprising the steps of: deep drawing and punching in a follow-up tool the connecting flange (2) and the tube section (3) so as to form them integrally in a first manufacturing step, deep-drawing the centering part (6, 6A, 6B) in a second manufacturing step and, in a third manufacturing step, pressing the centering part (6, 6A, 6B) into the connecting flange (2) and into the tube section (3). 